The present invention relates to an engine control device, and particularly relates to an engine control device capable of restarting the engine when a traffic light changes to green while the engine is stopped, for example, waiting for the traffic light.
The fuel consumption due to idling can be reduced by stopping the engine when the vehicle is stopped waiting for a traffic light at an intersection or stopped on a road due to the traffic congestion.
In order to reduce the fuel consumption by stopping the engine while the vehicle is stopped under these circumstances, a vehicle is developed provided with an engine control device, which stops the engine while the vehicle is stopped during travelling, and restarts the engine at the time of restarting the vehicle.
One conventional example of such an engine control device is disclosed in Japanese Unexamined Patent Application, First Application No. Hei 4-246252, which detects travelling information such as the vehicle speed, the depressed (ON)/released (OFF) state of the accelerator, etc., and stops the engine temporarily when the vehicle is stopped based on the above-mentioned travelling information, and restarts the engine when the transmission is in low gear, the clutch is applied (ON), and the accelerator is also depressed (ON).
Another example is disclosed in Japanese Unexamined Patent Application, First Application No. Hei 9-209790, in which the engine is restarted when the brake is released.
However, in conventional engine control devices, particularly in the conventional engine control devices, in which the engine is restarted when the brake is released, the following problem arises in contrast to the fact that these control devices are advantageous to the safety of the driver because these devices restart the engine after the braking is released. That is, the problem is that, since it takes time for sequential operations from releasing the brake pedal to depressing the accelerator pedal for restarting the engine, and a delay may occur in restarting the vehicle even if the driver wishes to start the vehicle immediately, which results in causing traffic congestion near the intersection.
It is therefore an objective of the present invention to provide an engine control device, capable of starting the vehicle by restarting the engine without a delay contrary to the driver""s will when the vehicle is started by restarting the engine in the idle stop state.
The first aspect of the present invention provides an engine control device comprising: an engine stop determination device for determining the appropriateness of stopping the engine; an engine stop device for stopping the engine based on the determination of the engine stop determination device; an engine start determination device for determining the appropriateness of starting the engine; an engine starting device for starting the engine based on the determination of the engine start determination device; and a vehicle forward signal state detecting device for detecting the state of a traffic light directly ahead of the vehicle travelling direction; wherein said engine start determination device determines whether it is appropriate to start the engine based on the change of the traffic light state detected by said vehicle forward signal state detecting device, when the engine is stopped by the determination of said engine stop determination device while the vehicle stops during driving.
The control device constituted as described above has the effect that the vehicle can be started according to the driver""s will by starting the engine, predicting the driver""s will, anticipating the change of a traffic light from red to green.
According to the second aspect, in an engine control device according to the first aspect, said engine start determination device starts the engine when the state of the traffic light detected by said vehicle front signal state detecting device changes from red to green.
According to the second aspect, it is possible to prevent traffic congestion due to the time lag in starting the vehicle by starting the engine without delaying other vehicles.
According to the third aspect, in the engine control device according to the first aspect, the change of the state of the traffic light detected by said vehicle front signal state detecting device is recognized by the traffic light color recognition processing.
According to the third aspect, since the state of the traffic light can be determined by a control device similar to the human judgement carried out by sight, it is possible to start the vehicle in conformity with the driver""s will without giving any feeling of unease to the driver.